I have a Sullivan starter using a Miller reduction unit on an 18 volt LiPo and have never had a problem using my starter. My engine usually starts within a couple of revolutions. I always rotate the prop backwards several revolutions before using the starter to make sure I don't have any hydraulic locks on any of the cylinders. I am using a Microsens on board glow system with balancer on a 3.7 volt 5600 MAH LiPo battery. Today I made a minor modification to my Howard DGA-12 to make it easier to assemble at the flying field. I made clips for the struts from tubing crushed twice at 90 degrees for mounting of the strut to the wing as suggested by one of my friends. This allows the struts to pivot and stay with the wing resulting in a lot less effort needed at the field for assembly.
Best wishes and good safe flying.
Heli-NuBee (AKA Roger the radial rabbit)